/*
 * Copyright 2011-2013 HTTL Team.
 *  
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *  
 *      http://www.apache.org/licenses/LICENSE-2.0
 *  
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package httl.spi.interceptors;

import httl.Context;
import httl.spi.Interceptor;
import httl.spi.Listener;
import httl.spi.Logger;
import httl.util.Optional;

import java.io.IOException;
import java.text.ParseException;

/**
 * Listener Interceptor. (SPI, Singleton, ThreadSafe)
 *
 * @author Liang Fei (liangfei0201 AT gmail DOT com)
 * @see httl.spi.translators.CompiledTranslator#setInterceptor(Interceptor)
 * @see httl.spi.translators.InterpretedTranslator#setInterceptor(Interceptor)
 */
public class ListenerInterceptor implements Interceptor {

    private Listener beforeListener;

    private Listener afterListener;

    private Logger logger;

    /**
     * httl.properties: before.listeners=httl.spi.listeners.ExtendsListener
     */
    @Optional
    public void setBeforeListener(Listener listener) {
        this.beforeListener = listener;
    }

    /**
     * httl.properties: after.listeners=httl.spi.listeners.ExtendsListener
     */
    @Optional
    public void setAfterListener(Listener listener) {
        this.afterListener = listener;
    }

    /**
     * httl.properties: loggers=httl.spi.loggers.Log4jListener
     */
    public void setLogger(Logger logger) {
        this.logger = logger;
    }

    public void render(Context context, Listener listener) throws IOException, ParseException {
        if (beforeListener != null) {
            try {
                beforeListener.render(context);
            } catch (Exception e) {
                if (logger != null && logger.isErrorEnabled()) {
                    logger.error(e.getMessage(), e);
                }
            }
        }
        try {
            listener.render(context);
        } finally {
            if (afterListener != null) {
                try {
                    afterListener.render(context);
                } catch (Exception e) {
                    if (logger != null && logger.isErrorEnabled()) {
                        logger.error(e.getMessage(), e);
                    }
                }
            }
        }
    }

}